use std::fmt;
use std::fmt::{Debug, Pointer};

// 使用 as 关键字提供新的名称
// use std::io;
use std::io::Result as IoResult;

enum IpAddrKind {
    V4(String),
    V6(String),
}

pub fn function1() -> fmt::Result {
    println!("same_mod function1.");

}

// pub fn function2() -> io::Result<()> {
pub fn function2() -> IoResult<()> {
    println!("same_mod function2.");

    let n = IpAddrKind::V4(String::from("a"));
    // io::Result::Ok()
}